CYP21A2 and congenital adrenal hyperplasia: KS and CAH resulting from 21OHD were suspected and then confirmed; in particular, karyotype analysis showed a 47,XXY polysomy, the biopsy of the testis revealed atrophied seminiferous tubules with Leydig cell hyperplasia, the ACTH stimulation test and CYP21 gene analysis were consistent with the diagnosis of nonclassical 21OHD.